Synthesis of 2-Quinolones based on Visible Light-Catalyzed Annulation of Diazo compounds

Herein, we report a photocatalytic method for the synthesis of 2-quinolones under mild conditions by employing alpha-diazo acetamide as substrates. The use of Eosin Y as a photocatalyst allows an economical and environmentally benign synthetic method. The process involves the generation of radicals from diazo compounds promoted by a visible-light-induced proton-coupled electron transfer (PCET) mechanism. The method demonstrates a broad substrate scope to provide various aryl- and alkyl-substituted 2-quinolones. To support the proposed mechanism, a series of mechanistic experiments were conducted. image